1. Field of the Invention
The present invention relates to an information processing apparatus such as an image forming apparatus, a monitor apparatus, and a monitoring system, which are configured to detect and control replacement or replenishment of consumables of the image forming apparatus.
2. Description of the Related Art
Conventionally, when consumables of an image forming apparatus are worn out or a remaining amount of the consumables becomes small, the consumables are replaced or replenished. In this case, inventory control of the consumables for replacement or replenishment is important in reducing downtime of the image forming apparatus. Therefore, methods are discussed to detect whether the remaining amount of the consumables is small or to see whether the consumables are replaced or replenished.
Japanese Patent Application Laid-Open No. 2003-39783 discusses a method in which an identification (ID) tag is attached to replacement or replenishment parts. An image forming apparatus checks the ID on a regular or occasional basis to see whether the ID is changed. In this way, the replacement or replenishment of the parts is detected. Although this is an appropriate method for detecting replacement, each part requires attachment of an ID tag, and further, an apparatus used for reading the ID has to be implemented in the apparatus main body. Accordingly, the cost of the main body and the parts is increased.
Japanese Patent Application Laid-Open No. 6-67532 and Japanese Patent Application Laid-Open No. 7-306582 discuss a method in which a switch is provided at a place where a replacement or replenishment part is installed. According to this switch, the replacement or replenishment part is detected when it is removed or attached, and therefore can be recognized to be replaced or replenished. However, according to this method, when the switch is turned on in a case other than replacement or replenishment, false detection may occur and detection accuracy will be significantly degraded. In a case of a toner cartridge unit for example, a cartridge is removed and shaken when toner level is low or removed when a paper jam occurs. Similarly, when a roller of a feeding roller unit runs idly, the roller is removed and reset after it is cleaned.
Further, Japanese Patent Application Laid-Open No. 7-25115 and Japanese Patent Application Laid-Open No. 2001-305920 discuss a method in which replacement or replenishment is detected based on a status of the image forming apparatus and a number of pages that have been printed. If a status indicating a replacement or replenishment time of the consumables is displayed, the consumables are regarded as replaced or replenished.
In this case, on a border of the detection, the status mayor may not appear. For this reason, once the status appears, the status is ignored for a certain period of time. For example, a number of pages which are printed at a time the status appears or disappears is stored and the status is not referred to until a certain number of pages is printed. According to this processing, a status which appears or disappears when the remaining amount of toner is small can be ignored until the replacement or replenishment is made so that detection error can be avoided. Further, a detection error which occurs when the cartridge is removed, shaken, and reset to temporarily suspend the toner low level, can be prevented.
However, according to the method discussed in Japanese Patent Application Laid-Open No. 7-25115 and Japanese Patent Application Laid-Open No. 2001-305920, when the toner level exceeds a predetermined threshold, a detection error occurs. It is therefore difficult to improve accuracy in detection while dealing with various situations.
For example, if toner in an image forming apparatus becomes empty when 300 pages are printed after a toner low occurs, a threshold of 1000 pages may be defined. In this case, although the toner low level is properly detected in normal use, if a print which requires only little toner is made, 1200 pages can be printed after the toner low sign appears. However, at the point 1000 pages are printed, toner low is detected again if the apparatus continues to be used without replacing the toner cartridge.
On the other hand, a detection error also occurs when making a print which consumes a large amount of toner. If a user supplies toner immediately after the toner low sign appears, and then makes a print which consumes ten times the amount of toner than a usual print, then toner low appears before 1000 pages are printed. Since this toner low is ignored, the case ends in a detection error. In order to avoid such a detection error, thresholds that can meet various situations need to be prepared. For example, an amount of toner consumed in making a print has to be determined, which makes the system complex.
As a result, conventional techniques require an expensive and special system such as an ID reading apparatus. Otherwise, appropriate control of the consumables becomes difficult when the consumables are replaced or replenished at the time the remaining amount of the consumables becomes small.